maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[Analysis] Validate the return type of s(n)printf like libcalls 

If the sprintf function is static (as on mingw-w64, where many stdio
functions are static inline wrappers), earlier optimization passes
could optimize out the return value altogether, and make it void,
which could break optimizations of this libcall that touch the
return value.

This fixes the issue discussed in PR37408 for the sprintf function.

Differential Revision: https://reviews.llvm.org/D46752

llvm-svn: 332106
This commit is contained in:
Martin Storsjo 2018-05-11 16:53:56 +00:00
parent 458506871a
commit 0d7c37756b
2 changed files with 25 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
llvm/lib/Analysis/TargetLibraryInfo.cpp
View File

@ -692,10 +692,12 @@ bool TargetLibraryInfoImpl::isValidProtoForLibFunc(const FunctionType &FTy,
case LibFunc_siprintf:
case LibFunc_sprintf:
return (NumParams >= 2 && FTy.getParamType(0)->isPointerTy() &&
FTy.getParamType(1)->isPointerTy());
FTy.getParamType(1)->isPointerTy() &&
FTy.getReturnType()->isIntegerTy(32));
case LibFunc_snprintf:
return (NumParams == 3 && FTy.getParamType(0)->isPointerTy() &&
FTy.getParamType(2)->isPointerTy());
FTy.getParamType(2)->isPointerTy() &&
FTy.getReturnType()->isIntegerTy(32));
case LibFunc_setitimer:
return (NumParams == 3 && FTy.getParamType(1)->isPointerTy() &&
FTy.getParamType(2)->isPointerTy());

21
llvm/test/Transforms/InstCombine/sprintf-void.ll Normal file
View File

@ -0,0 +1,21 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
@hello_world = constant [13 x i8] c"hello world\0A\00"
declare void @sprintf(i8*, i8*, ...)
; Check that a sprintf call, that would otherwise be optimized, but with
; optimized out return type, doesn't crash the optimizer.
define void @test_simplify1(i8* %dst) {
; CHECK-LABEL: @test_simplify1(
; CHECK-NEXT: call void (i8*, i8*, ...) @sprintf(i8* [[DST:%.*]], i8* getelementptr inbounds ([13 x i8], [13 x i8]* @hello_world, i32 0, i32 0))
; CHECK-NEXT: ret void
;
%fmt = getelementptr [13 x i8], [13 x i8]* @hello_world, i32 0, i32 0
call void (i8*, i8*, ...) @sprintf(i8* %dst, i8* %fmt)
ret void
}